I was trying to flash the files from the 202303 release, but I just tried again with the 202302 release and those flash fine.
cat /proc/mtd
dev: size erasesize name
mtd0: 00020000 00001000 "spl"
mtd1: 00300000 00001000 "uboot"
mtd2: 00100000 00001000 "data"